How to fix authenticator app

Question

how do is solve this as i cant access my authenticator app to login to my business account. getting

Error Code: 500121

[Moderator note: Personal information removed]

Answer 1

Hello @muna jason,

Thank you for posting your valuable question on Microsoft Q&A forum.   

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I'm very sorry for the inconvenience you’ve experienced, based on the details you shared.  

May I ask if you are the end-user or the IT admin of your organization? 

If you are the end-user, I would recommend you contact your organization account's Admin to reset your MFA settings through the Microsoft Entra Admin Center. If you haven’t yet reached out, here’s a helpful guide to locate your Microsoft 365 administrator: How do I find my Microsoft 365 admin? - Microsoft Support  

Ask your administrator to follow these steps:    

• Go to Microsoft Entra Admin Center: https://entra.microsoft.com  
• Navigate to Users > All Users.  
• Select your user account.  
• Go to Authentication Methods.  
• Click "Require re-register multifactor authentication".  

This will reset your MFA settings. The next time you sign in, you’ll be prompted to set up the Authenticator app again using a QR code.  

If you're an IT admin, please check to see if there are other IT admins in your organization who can help you with the reset. 

If you are the only administrator in your organization, this request cannot be handled through the Microsoft Q&A forum due to security and privacy limitations. In this case, you will need to contact the Microsoft Data Protection team, as they are the only group authorized and equipped with the necessary tools and verification procedures to confirm your identity and restore administrator access. 

Please try to find the related hotline number to call the frontline and let them raise a ticket for you: Customer service phone numbers - Microsoft Support 

Please carefully follow this instruction to ask for Microsoft Data Protection team support:   

Depending on your country or region. For some countries, when calling the support number, although there are about 30 seconds opening as something "you can visit the link...." But you can ignore this opening and wait until the option, then "1" as a business email user, "1" again for technical help.   

For some countries, it will be an automated conversation like:    

First, when you call the hotline, it asks what kind of problem you are worried about.   

Answered: authenticator.   

A: What kind of product are you using?   

B: Office 365 for business.   

A confirmation: education or company account?   

B: For companies   

A: Are you an administrator?   

B: Yes.   

A: Do you have the other admin in your organization?   

B: No.   

A: You need one.... Service request?   

B: Yes   

If your organization's Office 365 Business/Education subscription is from a partner or reseller, and the global administrator is unable to open a service request on your end, contact the reseller's support provider to help open a service request on behalf of you instead.   

Please understand that forum moderators have no control over user accounts, especially when it comes to logging in to your account, resetting your password, changing your access, etc.   

I hope you can successfully revoke your access. If you encounter any difficulties in contacting the frontline support, please feel free to let me know. Thank you and I wish you a great day!  

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Answer 2

To resolve issues with the Microsoft Authenticator app and access your business account, especially when you encounter an error like Error Code: 500121, you can follow these steps:

1. Alternative Sign-in Method: If you have any other sign-in methods available (like SMS or email), try using those to log in to your account.
2. Contact Administrator: If you're part of an organization, reach out to your Global Administrator. They can reset your Multi-Factor Authentication (MFA) settings, allowing you to configure the Authenticator app again.
3. Use the Admin Center: If you are the sole administrator, you can try to contact Microsoft support directly. You may need to call their customer service hotline and explain your situation, emphasizing that you are the only admin and are locked out of your account.
4. Create a Trial Tenant: If you cannot reach support, consider creating a trial Microsoft 365 tenant. This will allow you to access the Admin Center and submit a support ticket to the Data Protection team on behalf of your original tenant.
5. Follow IVR Prompts: When calling support, follow the prompts carefully. For example, indicate you are a business user and need technical support. Make sure to mention that you are the only administrator.

These steps should help you regain access to your account and resolve the issue with the Authenticator app.

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References:

• I cant log in to my business account because it is requiring Authenticator app which I do not have - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A